#include <Wire.h>
#include "SSD1306Ascii.h"
#include "SSD1306AsciiWire.h"

#define I2C_ADDRESS 0x3C

#define PIN1 5
#define PIN2 6
#define PIN3 7
#define PIN4 8
#define CLOCK 3
#define ENABLE 2
#define WAIT 1

SSD1306AsciiWire oled;

char msg[] = "Hello! MSX\n";
int index = 0;
int port[] = {PIN1, PIN2, PIN3, PIN4};

void setup() {
  pinMode(PIN1, OUTPUT);
  pinMode(PIN2, OUTPUT);
  pinMode(PIN3, OUTPUT);
  pinMode(PIN4, OUTPUT);
  pinMode(CLOCK, OUTPUT);
  pinMode(ENABLE, INPUT);
  digitalWrite(CLOCK, HIGH);
  
  Wire.begin();
  Wire.setClock(400000L);

  oled.begin(&Adafruit128x64, I2C_ADDRESS);
  oled.setFont(System5x7);
  oled.clear();

  while(digitalRead(ENABLE) == LOW)
    delay(100);
  oled.println("START!!");
}

void loop() {
  char c;
  
  c = msg[index++];
  for(int i=0; i<4; i++)
    digitalWrite(port[i], bitRead(c, i + 4));
  digitalWrite(CLOCK, LOW);
  delay(WAIT);
  
  digitalWrite(CLOCK, HIGH);
  delay(WAIT);
  
  for(int i=0; i<4; i++)
    digitalWrite(port[i], bitRead(c, i));
  digitalWrite(CLOCK, LOW);
  delay(WAIT);
  
  digitalWrite(CLOCK, HIGH);
  delay(WAIT);

  oled.print(c);
  if(c == '\n')
    while(1);
}